Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden of behavioral disclosure. It states the core action and filter capabilities, but omits return format, pagination, read-only nature, and any side effects. The mention of filtering by 'screener status' is misleading since no such parameter exists in the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise, with the core action in the first sentence and additional context in the second. The second sentence about Send16's unified inbox is not strictly necessary, but it is brief and does not detract much from the overall clarity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given six parameters and no output schema, the description is moderately complete. It lists several filter dimensions but lacks details on pagination, return structure, default behavior, and the screener status discrepancy. For a simpler tool, this might be acceptable, but here it leaves notable gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already provides 100% coverage for all six parameters, so the baseline is 3. The description adds minimal meaning by grouping filters (e.g., state, mailbox, label, search), but it also introduces a nonexistent 'screener status' filter, which is a negative. Overall, it does not significantly enrich the parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function: 'List inbox conversations.' It also names several filter dimensions, which helps clarify scope. However, it does not explicitly differentiate from sibling tools like get_convo or list_inbox_counts, so it doesn't earn a perfect 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage when one needs to list conversations, but it gives no explicit guidance on when to prefer this tool over alternatives or any exclusions. The context about unified inbox provides some situational background but not tool-selection guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.